v9fs: get rid of v9fs_dentry

->d_fsdata can act as hlist_head...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/9p/fid.c

@@ -43,25 +43,9 @@
 
 int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 {
-	struct v9fs_dentry *dent;
-
-	p9_debug(P9_DEBUG_VFS, "fid %d dentry %s\n",
-		 fid->fid, dentry->d_name.name);
-
-	dent = dentry->d_fsdata;
-	if (!dent) {
-		dent = kmalloc(sizeof(struct v9fs_dentry), GFP_KERNEL);
-		if (!dent)
-			return -ENOMEM;
-
-		INIT_HLIST_HEAD(&dent->fidlist);
-		dentry->d_fsdata = dent;
-	}
-
 	spin_lock(&dentry->d_lock);
-	hlist_add_head(&fid->dlist, &dent->fidlist);
+	hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
 	spin_unlock(&dentry->d_lock);
-
 	return 0;
 }
 
@@ -75,18 +59,18 @@ int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 
 static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
 {
-	struct v9fs_dentry *dent;
 	struct p9_fid *fid, *ret;
 
 	p9_debug(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n",
 		 dentry->d_name.name, dentry, from_kuid(&init_user_ns, uid),
 		 any);
-	dent = (struct v9fs_dentry *) dentry->d_fsdata;
 	ret = NULL;
-	if (dent) {
+	/* we'll recheck under lock if there's anything to look in */
+	if (dentry->d_fsdata) {
+		struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
 		struct hlist_node *n;
 		spin_lock(&dentry->d_lock);
-		hlist_for_each_entry(fid, n, &dent->fidlist, dlist) {
+		hlist_for_each_entry(fid, n, h, dlist) {
 			if (any || uid_eq(fid->uid, uid)) {
 				ret = fid;
 				break;

fs/9p/fid.h

@@ -23,26 +23,6 @@
 #define FS_9P_FID_H
 #include <linux/list.h>
 
-/**
- * struct v9fs_dentry - 9p private data stored in dentry d_fsdata
- * @fidlist: list of FIDs currently associated with this dentry
- *
- * This structure defines the 9p private data associated with
- * a particular dentry.  In particular, this private data is used
- * to lookup which 9P FID handle should be used for a particular VFS
- * operation.  FID handles are associated with dentries instead of
- * inodes in order to more closely map functionality to the Plan 9
- * expected behavior for FID reclaimation and tracking.
- *
- * Protected by ->d_lock of dentry it belongs to.
- *
- * See Also: Mapping FIDs to Linux VFS model in
- * Design and Implementation of the Linux 9P File System documentation
- */
-struct v9fs_dentry {
-	struct hlist_head fidlist;
-};
-
 struct p9_fid *v9fs_fid_lookup(struct dentry *dentry);
 struct p9_fid *v9fs_fid_clone(struct dentry *dentry);
 int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid);

fs/9p/vfs_dentry.c

@@ -83,18 +83,12 @@ static int v9fs_cached_dentry_delete(const struct dentry *dentry)
 
 static void v9fs_dentry_release(struct dentry *dentry)
 {
-	struct v9fs_dentry *dent;
+	struct hlist_node *p, *n;
 	p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
 		 dentry->d_name.name, dentry);
-	dent = dentry->d_fsdata;
-	if (dent) {
-		struct hlist_node *p, *n;
-		hlist_for_each_safe(p, n, &dent->fidlist)
+	hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
 		p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
-
-		kfree(dent);
 	dentry->d_fsdata = NULL;
-	}
 }
 
 static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)